Tractor-trailer fifth wheel coupling mechanism



7 TRACTOR-TRAILER- FIFTH WHEEL COUPLING MECHANISM Filed not. 31, 19151 July 7, 1953 w. J; GEDDERT 2 Sheets-Sheet 1 ubluam, yfi fieli 9 Q, 7 W l? July 7, 1953 2,644,693 I TRACTOR-TRAILER FIFTH WHEEL COUPLING MECHANISM Filed Oct. :51. 1951 W. J. GEDDERT 2 Sheets-Sheet 2 INVENTOR.

Patented July 7, 1953' TRACTOR-TRAILER FIFTH WHEEL COUPLING MECHANISM William J. Geddert, Alliance, Ohio, assignor to American Steel Foundries, Chicago, 111., a corporation of New Jersey Application October 31, 1951, Serial No. 254,021

3 Claims. (01. zsosaos) This invention relates to fifth wheels and more particularly to a novel fifth wheel coupling mechanism of the type disclosed in U. S. Patent 2,015,313, issued to Edmund P. Kinne.

In coupling mechanisms of this type, pivotally interconnected front and rear jaws are supported for translatory movement, with guide lugs or extensions of said jaws received in complementary guide slots which pivot the rear jaw upwardly to closed position as the jaws move forwardly and which accommodate pivotal movement of the rear jaw downwardly to open position as the jaws move rearwardly with respect to the fifth wheel. A lock is customarily pivoted to the fifth wheel on a substantially horizontal axis for pivotal movement downwardly to lock position with respect to the rear jaw when the latter is closed.

The front jaw is adapted for engagement by the king pin of a coupled vehicle, such as, for example, a semi-trailer, whereby said king pin wedges the front jaw forwardly against resilient means to compress the latter before the lock drops to locked position behind the rear jaw. Thus said resilient means is effective to maintain a slack-free condition between the parts of the coupling mechanism when the latter is coupled with the king, pin.

In prior art arrangements of this type, excessive coupling pressure by the king" pin against the front jaw is occasionally necessary to urge the jaw rearwardly against the resilient means to a point whereat the lock can dropto its locked condition. This phenomenon has been attributed to various causes such as binding of the lock extensions in the guide ways; however, no successful means have heretofore been provided for satisfactorily correcting this condition.

According to the present invention, it has been discovered that engagement of the king pin with the front jaw tends to tilt the latter on a substantially horizontal axis thereby tilting the pivot pin upwardly and tilting the rear jaw downwardly and rearwardly to increase its overlap with the lock. The guide lugs of the jaws normally limit such tilting; however, due to necessary commercialtolerances and wear of the parts in service, these lugs are frequently loose within their guide slots and accommodate sufficient tilting of the jaws so that excessive compression of the resilient means acting against the front jaw is required to move the rear jaw forwardly to a point whereat the lock may drop to locked position. I

Such prior art arrangements, for this reason, have either required excessively high coupling prior art arrangements has been excessive wear between the contacting areas of the front jaw and king pin during coupling. I 7

Accordingly, a primary object of the present invention is to eliminate tilting of the front jaw during contact of the king pin therewith during coupling, without the necessity of reducing clearance betweenthe jaw extensions and their guiding slots, an expediency which would result in prohibitive costs.

Another object of the invention is to devise an arrangement wherein tilting of the front jaw is positively prevented despite any wear which may take place in service between the lock extensions and the margins of their guide slots.

A further object of the invention is to reduce wear between the contacting areas of th front jaw and king pin during coupling.

' A morespecific object of the invention is to devise upper and lower abutments on the front jaw for substantially simultaneous engagement with complementary portions of the king pin during coupling.

The foregoing and other objects and advantages of the-invention will become apparent from a consideration of the following specification and the accompanying drawings, wherein:

Figure -1 is a perspective view of a preferred embodiment of the novel coupling mechanism applied to a conventional fifth wheel, which is illustrated in phantom lines.

Figure 2 is a side elevational view of the novel coupling mechanism in coupled relationship with i the king pin, the king pin and fifth wheel structure being diagrammatically illustrated in phantom lines for the sake of clarity;

Figure 3 is a view similar to Figure 2 but illustrating the coupling mechanism in fully open position preparatory to a coupling operation, and Figure 4 is an enlarged, fragmentary central vertical sectional view through the coupling mechanism during a coupling operation.

Describing the invention in detail, the preferred embodiment illustrated in the perspective view of Figure 1 is applied to a conventional fifth wheel 2, pivoted at each side thereof on a substantially horizontal axis as ate, to a bracket 6 adapted for attachment to the frame I of Y a vehicle (not shown) such as an automotive truck.

The novel coupling mechanism comprises front and rear jaws 8 and 10, respectively, pivotally interconnected to each other as at 12, by a pivot pin er other suitable means affording pivotal connection between the jaws on a substantially horizontal axis. The pin I2 also connects the jaws to each: other for translatory movement as a unit to't'h'e closed position shown in Figure 2 and to the open position shown in Figure 3; and it will be noted that these jaws are provided ateach side thereof with conventional; extensions or lugs M and I6, respectively, slidably: movablealong a conventional support and guide ledge l8 defining the lower margin of a guide-slot 2 re'-- ceiving said lugs l4 and I3 The-ledge l8"- terminates at its rear extremity in a downturned segment or portion 22 accommodating pivotal movement of the rear jaw I8 downwardly to its open position shown in Figure 3 as the jaws move rearwardly during withdrawal of a king pin 24 of a coupled vehicle, such as a. semi-trailer:

The rear jaw is lockedirr the: closedposition' of Figure 2 by a lock' generally" designated 26 which is pivoted as at" 28 on a substantiallyhorie zontal axis to the fifth wheel 2, said lock having oneor more legs 30 projecting forwardly from said axis 28 for abutment as at 32.with rearwardly facing surfaces of the rear jaw lU'to lock the jaws in the closed position-of Figure 2 whereat'the kin pin 24 is in coupled relationship confinedbetween the aws.

As best seen in Figure L the king pin 24 is provided at its lower end with a retainer flange 3| which in coupled position of the king pin underlies a retainer ledge or l'ug 33 formed asa segment of a ring on therear'w'ardly facing arcuate surface of the front jaw' Thus accidental uncoupling of the king pin 24 by upward movement thereof is positively prevented by abutment of the flange 31 with the ledge 33 of the front jaw 8.

The lock 26 is preferably resiliently biased to locked position thereof shown in Figure 2 by spring means herein illustrated in the form of a compression spring 35 compressed between the leg 30 and an overlying surface of thefifth wheel 2, although it will be understood that other forms and combinations of springs may be utilized for this purpose, as disclosed in a c'o-pe'ndingKayler application, Serial No. 105,080, filed July 16', 1949.

The lock 2 6 is pivoted upwardly to unlocked position by any desired conventional operating means, such as those described in said co-pending application whereupon the king pin 24 may be withdrawn from the coupled position thereof by forward movement of the fifth wheel 2 or by rearward movement of the king pin 24, whereupon the jaws assume the fully open position of Figure 3-.

The forward surface of the front jaw 8 bears in the usual manner against spring means in the form of a block 38' of resilient material such as rubber which is compressible between the lock 8 and a front wall 39 of the fifth wheel as the king pin moves the jaw 8 forwardly during a coupling operation until the lock leg 3|] drops from the. lock supporting surface 36 of the rear jaw 10 to engage its surface 32, whereupon coupling is completed and the block 38 iseffective to maintain the parts in a slack-free condition.

In prior art arrangements of this type, relative forward movement of the kingpin 24 to the left, as seen in Figure 3, during a coupling operat1on caused engagement of the king pin with the front jaw 8 adjacent the upper extremity thereof tending to tilt the front law 3 pw rd y about a horizontal axis forwardly of the pivotal connection at l2 to the rear jaw 10. Thus, if the jaw extensions 14 and It were sufficiently loose within the guide slots 20, the above described pivotal movement of the front jaw 8 moved the axis 12 upwardly causing downward and rearward movement; of the lock supportingsurface tfiof the rear jaw 10. Under these conditions, greater than normal forward movement of the front jaw 8 was required to permit downward movementof the lock leg 30 from the surface 36 to: the surface 32 against which the leg 30 bears in locked position of the lock 26. For this reason; greater" than normal compression of the resil'ient'block' 38 was required during coupling.

In'accordan'ce with the present invention, the frontjaw &is.formed with abutment surfaces 40 and 42 above and below its ledge 33 as well as the horizontal plane of its center of gravity. The surfaces 40 and 42 are adapted for substantially simultaneous engagement with the king pin 24 and with its retainer flange 3.1:, respectively, as best seen in Figure: 4; By means: of this novel arrangement", tilting orpivoting or the frontij'aw 8 is positively prevented during forward movement thereof asthe. king pin. 2.4. moves the front jaw 8 forw-ardly'tc: compress theblock 3'8 accommodati'ng movement of both. jaws: to a. point whereat' the lock leg 30 may drop to the locked position shown in" Figure; 2.

It will be further understood that by means of the novel arrangement, commercial tolerances may be observed in the manufacture of the lock extensions It and It; aswell as the slot 20, inasmuch as reasonable looseness of the extensions within the slot may be afforded without causing coupling difliculties. device is capable of much longer life in service inasmuch as wear of the lugs l4 and I6 and the margins of their slot 20 will not interfere with ease of coupling.

1' claim: I .1. In a fifth. wheel coupling mechanism; the combination. of front and rear jaws pivotally interco'nnected for translatory movement forwardly and rearwardly with respect to the fifth wheel, a guide. ledge. on the fifth wheel engaged with an extension on the rear jaw for pivoting the rear jaw upwardly to. closed position thereof during forward. movement of the jaws, compression. spring means between the front jaw and a front. wall of said fifth wheel for yieldingly resisting. forward movement of said jaws to the closed position. of said rear jaw, and vertically aligned rearward-1y facing king pin abutments on the front jaw above and below the horizontal plane of its center of gravity.

2'. In a fifth wheel couplingv mechanism; the combination of front and rear jaws pivotally interconnected. for translator-y movement forwardly and, rearwardly with respect to the fifth wheel, lateral extensions on said. jaws received within guide slotsof said fifth wheel, said slots having downturned rear extremities accommodating pivotal movement of the, rear jaw downwardly to open position thereof during rearward movement of the jaws, a lock engageable with an upwardly facing surface of the rear jaw in open position thereof and engageable with a rearwardly facingsurface of the rear jaw in closed position thereof, spring means between the front jaw and a front wall of the fifth wheel for resisting forward movement of the jaws to the closed position of the rear jaw, an abutment on the Furthermore, the improvedv front jaw between its upper and lower extremities adapted to overly a retainer flange of an associated king pin confined between said jaws in closed position thereof, and vertically aligned king pin abutment surfaces on said front jaw above and below said abutment.

3. In a fifth wheel coupling mechanism for a king pin having a retainer flange; the combination of hinged front and rear jaws having lateral extensions received Within guide slots of said fifth wheel, a downwardly facing abutment on the front jaw for engagement with a retainer flange of said king pin to limit upward movement 0 Number 5 flange during coupling or bufiing.

7 WILLIAM J. GEDDERT.

References Cited in the file of this patent UNITED STATES PATENTS Name Date 2,015,313 Kinne Sept. 24, 1935 

